Glilot Capital and Sienna Venture Capital jointly led Series A financing, raising the total funding to $35 million

New York and Tel Aviv, Israel, October 8, 2026 / PRNewswire / -- AI, a native runtime security platform for enterprises, announced today that the company has completed a $25 million Series A financing round, bringing the total funding raised to date to $35 million. This financing round was co-led by Glilot Capital and Sienna Venture Capital, with Corner Ventures, Atlacle, and RNP Capital Advisors also participating in the investment.

At the time this financing was secured, companies were rapidly deploying AI agents. These agents have increasingly broader access to business systems, data, and work processes, introducing a new type of security risk that traditional methods were not designed to detect or prevent. According to data from Gartner, by 2027, the AI security market is expected to approach $4.8 billion, representing a 68.7% increase from 2026; by 2028, it is expected to reach nearly $7.7 billion. As the adoption of AI agents accelerates and these agents become more autonomous, companies face two types of security challenges: they must protect the agents they have built themselves as well as defend against increasingly powerful AI-driven attacks.

Rein attempts to address both aspects simultaneously. Its platform is built on patented sidecar technology and operates at runtime, on the nodes that execute the proxy actions. This enables the security team to see every line of code executed by the proxy and every resource it accesses, allowing for governance of proxy activities and the provision of protection measures that can stop harmful behavior in real time. Rein also protects the proxy supply chain and does not forward company or customer data through gateways or proxy servers.

Rein Security, co-founder and CEO, along with Matan Bar and Efrat, stated: "Enterprise AI agents are becoming the core of business operations, but security capabilities have not kept up with the autonomy that these systems now possess. This financing will help us continue to build the infrastructure required for deploying AI agents, enabling enterprises to use AI agents with visibility, control, and confidence."

Enterprises adopt AI proxies at a faster pace than their security protection capabilities, and most of the risks brought by these proxies are both new and concealed. The risks lie in the downstream actions they automatically perform within various business systems; these actions are often triggered not by humans, but by another system or proxy that sends instructions. Protecting against such proxies requires understanding every action they perform and preventing harmful ones. The same is true for adversarial AI; it launches attacks at machine speed and can overwhelm security teams. This necessitates a completely different approach: shifting the focus from threat intelligence and vulnerability management to a more proactive method that prioritizes prevention and protection.

The Arik Kleinstein of Glilot Capital indicates that "the proxy economy has arrived, and the rapid adoption of AI proxies is bringing fundamental changes to corporate security. As proxies gain the ability to access systems, make decisions, and act autonomously, companies need a new approach tailored to this new environment. This is a rapidly changing field with insufficient supply in terms of security, and Rein possesses the platform, vision, and early progress to help define this field."

The risks identified by Rein have now appeared in production environments. For example, on Black Hat USA 2026, the vulnerability research team of Rein Agent Breakers demonstrated how they were able to breach the AI shopping proxy of one of the top five retailers in the United States, indicating that the speed at which AI is adopted is far exceeding its security capabilities. Furthermore, an employee proxy of a global company opened what seemed to be an ordinary PDF; however, the file contained hidden instructions for injection, directing the proxy to perform actions beyond its intended role. Rein detected and prevented this behavior before any damage was caused.

The Thomas Visan of Sienna Venture Capital indicates that as corporate technology ecosystems continue to expand and incorporate more AI agents that directly affect the production environment, security issues become increasingly important. The existing frameworks are clearly unable to cope with this transformation. Rein Differentiated platforms are specifically designed to address current and new agentic AI security threats, enabling companies to occupy a unique position in this rapidly evolving market.

Respond to the growing demand for stronger protection against AI proxies

Against the backdrop of significant revenue and customer growth, Rein will utilize the new funds to accelerate product innovation, advance agentic research, and support global recruitment. Since its launch in January 2026, the revenue of Rein has increased by 8 times, and the number of customers has grown by 5 times.

New customers, including Flex and Swimlane, have further expanded the coverage of Rein in industries such as financial services, healthcare, SaaS, data, retail, and energy.

As enterprises build and deploy increasingly powerful AI proxies, Rein has seen a growing demand for security solutions that can keep up with the rapid adoption of these proxies. The company's platform currently protects thousands of AI proxies, which have executed millions of actions, including those for Dun and Bradstreet, as well as for the digital-first insurance company Lemonade. Rein provides protection for the AI proxies of Lemonade, supporting businesses that serve over 3 million active customers; it also provides protection for the proxies of Dun and Bradstreet, enabling the agentic products that serve more than 240,000 customers.

Dun & Bradstreet, Chief Cybersecurity and Technical Risk Officer, Jay DePaul stated: "Our customers rely on Dun & Bradstreet to provide reliable data, and this trust must extend to every AI agent that we put into production. Rein helps us to observe and control the behavior of these agents on a scaled-out level, allowing us to continue to innovate with the help of agentic & AI while also protecting our customers who depend on us."

In recent months, Rein has also gained recognition from a broader community of technology and cybersecurity professionals. The company was selected for AI Conference's Start Up Showdown, becoming one of the 8 early-stage companies competing in the program; it was also rated by TechCrunch as one of the top 200 in the Startup Battlefield category, ranking among the most promising early-stage startups in the field of cybersecurity.

For more information, please visit www.reinsec.io.

About Rein Security:Rein Security is a agentic AI security company dedicated to providing agency services for enterprises. With its patented real-time architecture, Rein can offer complete visibility and protection for each enterprise agent – tracking every action back to the line of code that triggered it and correlating it with business outcomes. Rein Security is trusted by leading Fortune 500 companies and has received support from Glilot Capital, Sienna Venture Capital, and Corner Ventures. Founded in 2024, it is headquartered in New York City and Tel Aviv.

Media contact:Bateman Agency for Rein Security